1. Field of Invention
The present invention relates generally to the field of electronic writing tablets. More specifically, the present invention is related to a writing pad with flexure sensors retained therein.
2. Discussion of Prior Art
When a computer is associated with written pages, a method for relating the pages to data in the computer is needed. Information such as where on a page, what number page, how many pages have been removed or turned is needed to correlate the physical pages to the data in the computer. At the present time, the prior art has failed to teach a system which accurately electronically identifies turned or removed pages from a writing tablet.
U.S. Pat. No. 4,636,881, to Brefka et al., describes a talking book with a left and right infrared detectors used to detect page turning. However, Brefka provide a limited means of detectionxe2x80x94only detecting a left to right transfer of pages.
U.S. Pat. No. 5,569,868, to Leung, describes a sound generating book including a plurality of sensors, including transmitters and receivers, positioned at various places in the book. The sensors enable capacitive measurement and correlation with position thereof.
The available prior art described hereafter is limited to descriptions of pressure detection demarcations and use of conductive inks.
U.S. Pat. No. 5,764,221 to Willard (assigned to Willard Technologies) describes an electronic data collection system wherein a flexible data entry sheet covers a matrix of sensors. A user marks the sheet in a specified area and the detectors associate the mark position with a response to a question. Willard, however, fails to detect removed or turned pages and associate these actions with event driven actions. The article xe2x80x9cThe Paper Computerxe2x80x9d, http://www.papercomputer.com/PpC-folder/ppc-home.htm, describes an apparent product version of the above patent.
U.S. Pat. Nos. 3,719,261; 3,834,301; 3,995,729; 4,369,269, and 5,829,904 each describe the use of conductive inks in printing, but fail to include sensors or contacts included with pages to detect changes in resistance of the pages associated with turning or removal thereof.
Whatever the precise merits, features and advantages of the above cited references, none of them achieve or fulfills the purposes of the present invention. The present invention enables electronic detection of turned or removed pages from a writing tablet. These and other objects are achieved by the detailed description that follows.
A writing pad for use with a computer includes a number of sheets each having a flexure sensor affixed thereto. Circuitry connected to the sensors determines whether the sheets are lifted and removed from the pad, whereby the particular sheet currently in use may be identified. Alternative embodiments include using the elements of the invention in various configurations such as: a one or multiple-part checkbook systems with recognition of check writing environment, as a children""s book to add sound to identified pages, as an answer sheet for testing or voting, in a clipboard configuration or to assist a speaker during a slide-show presentation. The flexure sensors include resistive structures such as carbon based goo, transducers, conductive inks, strain gauges, patterned dissolved graphite, embossed sensors or other pressure/flexure sensors or equivalents thereof.